Process for the safe handling of c{11 {11 and c{11 {11 acetylenic hydrocarbons

ABSTRACT

An improved safe method for the handling, concentration, purification, storage, and transportation of C3 and C4 acetylenic hydrocarbons involves contacting a gas stream that contains 10 mole percent or less of these compounds with activated carbon to form compositions that comprise activated carbon on whose surface about 2 percent to 10 percent, based on the weight of the carbon, of C3 and/or C4 acetylenic compounds have been adsorbed. These activated carbon compositions, which are air stable and which cannot be detonated, can be handled, stored and transported without appreciable danger of explosion. Concentrated and purified acetylenic compounds can be recovered by stripping the carbon with, for example, a nitrogen-methylene chloride mixture. Further improvement in the safety of the method results when the pyrolysis gas is diluted with an inert, non-explosive gas that has carbon adsorption characteristics similar to those of the C4 acetylenic compounds prior to the treatment of the activated carbon with the pyrolysis gas stream.

United States Patent Walker et a1.

[ 1 Dec. 19, 1972 [541 PROCESS FOR THE SAFE HANDLING OF c, AND c,ACETYLENIC HYDROCARBONS [72] Inventors: David G. Walker, Baytown; DonaldA. Keyworth, Houston, both of Tex.

[73] Assignee: Tenneco Chemicals, Inc.

[22] Filed: Nov. 20, 1970 21 Appl. No.: 91,567

[52] U.S. Cl ..55/63, 55/74, 260/260 A [51] Int. Cl. ..B01d 53/02 [58]Field of Search ..55/59, 63, 74, 387, 79, 179;

' 260/677 AD, 679 A, 681.5; 208/99, 310;

Spangler ..55l74 Primary Examiner-Charles N. l-lart Attorney-Daniel J.Reardon, Barry G. Magidoff and Evelyn Berlow [57] ABSTRACT An improvedsafe method for the handling, concentration, purification, storage, andtransportation of C, and C, acetylenic hydrocarbons involves contactinga gas stream that contains 10 mole percent or less of these compoundswith activated carbon to form compositions that comprise activatedcarbon on whose surface about 2 percent to 10 percent, based on theweight of the carbon,'of C, and/or C acetylenic compounds have beenadsorbed. These activated carbon compositions, which are air stable andwhich cannot be detonated, can be handled, stored and transportedwithout appreciable danger of explosion. Concentrated and purifiedacetylenic compounds can be recovered by stripping the carbon with, forexample, a nitrogen-methylene chloride mixture. Further improvement inthe safety of the method results when the pyrolysis gas is diluted withan inert, non-explosive gas that has carbon adsorption characteristicssimilar to those of the C, acetylenic compounds prior to the treatmentof the activated carbon with the pyrolysis 7 gas stream 18 Claims, NoDrawings PROCESS FOR THE SAFE HANDLING OF C3 AND C4 ACETYLENICHXDRQCA'LBQNS a." V..

This invention relates to a method for the safe handling of acetyleniccompounds that have three or four carbon atoms. More particularly, itrelates to a safe method of concentrating, isolating, transporting,storing, and using methylacetylene, diacetylene, vinylacetylene, andmixtures of these compounds.

The high temperature pyrolysis of hydrocarbons yields acetylene,hydrogen, carbon dioxide, carbon monoxide, and small amounts of otherunsaturated hydrocarbons that contain from two to 10 or more carbonatoms. The unsaturatedhydrocarbons that have three or four carbon atoms,that is, methylacetylene, allene, diacetylene, and vinylacetylene, aregenerally present in thepyrolysis gas streams in the amount of about 5percent to percent, based on the weight'of acetylene in the gas stream.After removal of the acetylene from them, the gas streams contain about1 percent to 10 percent by weight of the C and C acetylenic compounds.

While the C and C acetylenic compounds are potentially valuable asreactants in the manufacture of a number of chemical products, they havenot been used to any appreciable extent in these applications because ofthe difficulties and hazards involved in isolating them from the gasstreams. The concentration of these compounds in the gas streams andtheir separa: tion by fractional distillation procedures are dangerousto carry out because diacetylene is extremely sensitive and candecompose explosively in the gas phase at temperatures above -C. Itscritical pressure for explosion is only 0.041 atmosphere absolute. Ithas been reported that this critical pressure can be raised to about 1atmosphere absolute by diluting the diacetylene with a sizeable amountof a non-explosive inert gas, such as ammonia, carbon dioxide, sulfurdioxide, nitrogen,

propane, butane, butylene, and the like. The resulting gas streams thatcontain less than about 10 percent by weight of the acetylenic compoundsdo not deflagrate even at extremely high total gas pressures andtemperatures. Attempts to use the acetylenic compounds in these dilutegas streams as reactants have been unsuccessful because of problemsinvolving catalysts and other reactants caused by the inadequateresidence times of the acetylenic compounds in the reaction vessel. Fortheir use as reactant to be practical, the C and C acetylenic compoundsshould be made available with as little diluent gas as is consistentwith safety.

In accordance with this invention, a safe and efficient method has beendeveloped for the separation of.C and C, acetylenic compounds from gasstreams that contain less than about 10 percent by weight of thesecompounds. The acetylenic compounds are obtained in a concentrated formthat can be safely and easily handled stored, and transported and fromwhich the acetylenic compounds can be recovered quantitatively and insubstantially pure form. In the method of this invention C and Cacetylenic compounds are safely and efficiently removed from gas streamsthat contain 10 percent or less of these compounds by contacting the gasstreams with activated carbon. The carbon adsorbs the C and C acetyleniccompounds quantitatively until its surface is saturated. The adsorbedacetylenic compounds do not polymerize'to any noticeable degree onprolonged storage at ambient temperature.

veniently handled, stored, and transported. The

acetylenic compounds can be readily recovered from them by passing astream of inert gas, through the bed of gas-saturated carbon until allof the acetylenic compound has been desorbed. The resulting gas stream,which contains about 30 to mole percent of C and C acetylenic compoundsin an inert gas, can be used as a source of the acetylenic compounds invarious reactions. Illustrative of the inert gases that can be used todisplace the adsorbed acetylenic compounds are steam andnitrogen-methylene chloride mixtures. The preferred inert gas is amixture comprising 50 to 75 mole percent of nitrogen and'25 to 50 molepercent of methylene chloride. Particularly satisfactory results havebeenobtained using nitrogen saturated with methylene chloride at ambienttemperature.

While the aforementioned method provides. a generally safe and efficientmeans'of handling, storing, transporting, concentrating, and isolatingthe C and C acetylenic compounds, occasionally the conditions underwhich the acetylenic compounds are being desorbed from the carbon aresuch that there is local overheating and a mild deflagration of the gasmixture occurs. In a preferred embodiment of this invention, theaforementioned method is modified to eliminate the possibility that theacetylenic compounds in the gas stream will deflagrate during handlingor storage. ln

this modified process, a stable, non-explosive compound that hasapproximately the same affinity for carbon as the C acetylenic compoundsis added to the gas streambefore it is broughtinto contact with theactivated carbon. The gas stream is diluted to such an extent that itwill not propagate a deflagration even with vigorous initiation, forexample, using a white hot platinum wire as a detonator. .The pyrolysisgas stream is ordinarily mixed with about 30 percent to 70 percent ofits weight, and preferably about 45 percent to percent of its weight, ofsaid diluent.

The diluents that are used in this process are stable, non-explosivecompounds that are non-reactive toward the acetylenic compounds and thathave an affinity for carbon adsorption that is similar to that ofdiacetylene and vinylacetylene. They preferably have distributionnumbers of about 0.4 to 3.0 for diacetylene and vinylacetylene. Thedistribution numbers are obtained by measuring the distribution of thecompounds between activated carbon and the gas phase and using thefollowing equation:

U- (for C4Hg) [C H on carbon] [inert compound in gas phase] n Q H in gasphase] [inert compound on carbon] Illustrative of the stable,non-explosive diluents that can be used in the practice of thisinvention are the fol- Particularly satisfactory results havebeenobtained using a gas stream that contained substantially chloride, thereis obtained a gas stream that comprises 20 to 50 mole percent of theacetylenic compounds and 20 to 50 mole percent of n-butane. This gasstream can be safely added to reaction vessels in which the acetyleniccompounds are to. be used as reactants. For example, it can be added toa dilute solution of a halogen compound to form polyhalogenatedhydrocarbons. This process is described in detail in our copendingapplication Ser. No. 91,566, which was filed on Nov. 20, 1970. I q

The gas streams that comprise C and C acetylenic compounds and n-butaneor another inert, non-explosive gas having a distribution number ashereinbefore defined in the range of about 0.4 to 3.0 can be used assuch in halogenation or other reactions. Alternatively, the process canbe modified to separate the C compounds from the C compounds or to yieldsubstantially pure diacetylene. in each case the product is a mixture ofthe acetylenic compound or compounds with an amount of n-butane oranother inert non explosive compound that overcomes the tendency of theacetylenic compounds to deflagrate.

In the practice of this invention a gas stream that contains about 1mole percent to 10 mole percent of acetylenic compounds having 3 or 4carbon atoms is brought into contact with activated carbon until thesurface of the carbon is saturated with these acetylenic compounds. Theconditions under which this process is carried out are not critical. Itis generally most convenient to carry it out at atmospheric pressure andat ambient temperature. If desired, other temperatures and pressures canbe used. The process is ordinarily carried out by passing the gas streamthrough standard carbon-packed columns. A plurality of columns is usedso that the carbon in one column can be stored, transported, stripped,or otherwise used while another column is on stream.

The activated carbons that can be used in the process of this inventionare prepared by heating a carbonaceous material of vegetable, animal, ormineral origin at temperatures above 400 C. until the material iscompletely carbonized. Among the materials from which the activatedcarbons may be prepared are coal, coconut shells, wood dust, peat,petroleum residues, and the like. The carbon should have an initialadsorption capacity for carbon tetrachloride at ambient temperatures ofat least 8 percent, since those of lower capacity are deactivated toorapidly to be economically practical. High surface area carbons thathave an initial adsorption capacity for carbon tetrachloride of 50percent or more are not ordinarily used in the practice of thisinvention because they add to the cost of the process without providinga corresponding improvement in its efficiency. The activated carbon isusually employed as a finely-divided powder having a particle size ofabout 10 to 200 mesh. Particularly good results have been obtained usingactivated carbon prepared by heating coal in steam at 700-900 C. Onesuch material, which is marketed as Pittsburgh Type SGL, hasthefollowing characteristics:

s x 30 (U.S. Sieve Series) 0.48 gJml. 0.85 mLIgram Particle Size DensityTotal Pore Volume Pore Volume Distribution (l) 25 A.

The quantity of activated carbon that is used is not critical anddepends to a large degree on the amount of C and C, acetylenic compoundsthat are present in the gas stream.

The C and C acetylenic compounds that are adsorbed on the surface of thecarbon can be desorbed by contains 1 to 10 mole percent of C and Cacetylenic compounds is passed into a first bed of activated carbon, andthe gas leaving the first bed is passed into a second bed of activatedcarbon until the surface of the carbon in the first bed is saturatedwith C, acetylenic compounds (diacetylene and vinylacetylene) and thesurface of the carbon in the second bed is saturated with C compounds(methylacetylene and allene). Treatment of the first bed of saturatedcarbon with a stream of nitrogen saturated with methylene chloride atambient temperature results in the formation of a gas stream thatcontains about 20 to 50 mole percent of the C, acetylenic compounds innitrogen. When this gas stream is passed through a sulfuric acidscrubber, the vinylacetylene is removed from it, and there is obtained agas stream that contains about 20 to 30 mole percent of diacetylene andto mole percent of nitrogen. Passage of this gas stream through a liquidnitrogen trap yields substantially pure diacetylene. Treatment of thesecond bed of saturated carbon with a stream of nitrogen saturated withmethylene chloride at ambient temperature results in the formation of agas stream that contains about 20 to 50 mole percent of.

methylacetylene and allene in nitrogen.

The invention is further illustrated by the examples that follow.

EXAMPLE 1 A. A gas mixture obtained by the pyrolysis of natural gas hadthe following composition:

Moles per Million Moles of Gas l060ll 0163 C Acetylenic CompoundsHydrogen 550,000 Carbon Monoxide 270,000 Acetylene 75,000

, Methane 65,000 Carbon Dioxide 35,000 Ethylene I 4,000 Diacetylene I1,700 Methylacetylene allene 1,200 Vinylacetylene 800 AromaticHydrocarbons 600 C Acetylenic Compounds 40 After the removal of most ofthe acetylene from it, the gas stream contained 3.7 ,mole percent ofdiacetylene, 1.7 mole percent of methylacetylene and allene, 1.3 molepercent of vinylacetylene, and small amounts of acetylene and butadiene.This gas stream was passed at ambient temperature and atmosphericpressure through a two-foot bed that contained 400 grams of activatedcarbon (Pittsburgh Type SGL) until the carbon was saturated. A total of34 grams (8.2 percent by weight) of the following mixture of compoundswas adsorbed on the carbon:

Mole Percent Weight Percent Diacetylen 5 .5 58.7 Vinylacetylene 34.035.0 Methylacetylene allene 3.3 I 2.8 Acetylene 4 2.8 I 1.5 Butadiene1.4 2.0

The saturated carbon was stripped by passing through the bed a stream ofnitrogen that was saturated with methylene chloride at room temperature.The resulting gas stream contained about 30 to 50 mole percent ofdiacetylene and vinylacetylene and 50 to 70 mole percent of nitrogen.

B. The gas stream that contained diacetylene, vinylacetylene, andnitrogen was passed through a sulfuric acid scrubber which removed thevinylacetylene from it. There was obtained a gas stream that containedabout 25 mole percent of diacetylene and 75 mole percent of nitrogen.Passage of this gas stream through a liquid nitrogen trap yieldedsubstantially pure 96 percent) diacetylene.

EXAMPLE 2 A gas stream that contained 3.7 mole percent of diacetylene,1.7 mole percent of methylacetylene and allene, 1.3 mole percent ofvinylacetylene, and smaller amounts of acetylene and butadiene and thatwas obtained by the removal of most of the acetylene from a hydrocarbonpyrolysis gas stream was passed at 0.8 atmosphere pressure and ambienttemperature through a primary carbon bed that contained 400 grams ofactivated carbon (Pittsburgh Type SGL). The gases leaving this bed werepassed through a secondary carbon bed that contained 400 grams ofactivated carbon (Pittsburgh Type SGL).

At the start of the treatment, the C and C acetylenic compounds wereadsorbed quantitatively by the activated carbon in the primary carbonbed. As the passage of the gas stream through the carbon beds wascontinued, the C acetylenic compounds were retained on the primarycarbon bed, while the C acetylenic compounds were desorbed by theprimary carbon bed and then adsorbed by the secondary carbon bed.

eras

The carbon bed on which the C acetylenic compounds had been adsorbed andthat on which the C acetyleniccompounds had been adsorbed were storedfor 5 days during which time the adsorbed acetylenic compounds did notpolymerize to any noticeable extent. The saturated carbons, whichcontained 5-8 percent by weight of the acetylenic compounds, could notbe detonated by vigorous pounding with a hammer and anvil. The saturatedcarbons were air stable. They could be ignited easily by a spark or openflame, and they burned rapidly with a very sooty flame.

The acetylenic compounds were recovered from the saturated carbons bypassing through the carbon beds a stream of nitrogen saturated withmethylene chloride at ambient Y temperature. There were obtained a gasstream that contained about30 to 50 mole percent of methylacetylene andallene and 50 to mole percent of nitrogen and a gas stream thatcontained about 30 to 50 mole percent of diacetylene andvinylacetyleneand 50 to 70 mole percent of nitrogen. I v

EXAMPLE 3 A gas stream that contained 3.7 'mole percent of diacetylene,1.3 mole percent of vinylacetylene, 1.7 mole percent of methylacetyleneand allene, and 5.0 mole percent of n-butane was passed at atmosphericpressure and ambient temperature through a primary carbon bed thatcontained 400 grams of activated carbon. The gases leaving this bed werepassed through a secondary bed that contained 400 grams of activatedcarbon. The gas stream was passed through the carbon beds'until thecarbon in the primary bed was saturated with C compounds and the carbonin the second bed was saturated with C compounds.

Thecarbon in the primary bed was subjected to a rapid steam purge atatmospheric pressure until all of the C, compounds had been removed fromit. No deflagration occurred during the steaming. Analysis of therecovered gas indicated that it contained about 34 mole percent ofdiacetylene, 20 mole percent of vinylacetylene, and 46 mole percent ofn-butane.

EXAMPLE 4 The procedure described in Example 3 was repeated using eachof the following inert non-explosive compounds in place of the n-butane:

a. Propane b. lsobutane c. lsopentane d. Pentane e. Butylene f.Pentylene g. 2,2-Dimethylpropane h. Ethyl chloride i. Methyl bromide Ineach case the gas mixture contained 40 to 60 mole percent of the Cacetylenic compounds based on the total amount of C acetylenic compoundsand inert non-explosive compound. The gas mixtures were passed throughbeds of activated carbon. The carbon beds were then treated with steamto generate gas streams that contained 30 to 50 mole percent of the Cacetylenic compounds and 50 to 70 mole percent of the inertnon-explosive compounds.

mole percent of said acetylenic compounds that comprises the steps of Va. passing said hydrocarbon pyrolysis gas through a bed of activatedcarbon until the surface of the carbon is saturated with adsorbedacetylenic'compounds having thr'ee'or four carbon atoms and b. passing astream of inert gas through the bed of saturated activated carbonthereby desorbing the- 2. The process of claim 1 wherein in Step (a)the. hydrocarbon pyrolysis gas is passed into a first bed of activatedcarbon and the gas leaving said first bed is passed into a second bed ofactivated carbon until the surface of the carbon in the first bed issaturated with diacetylene and'vinylacetylene and the surface of thecarbon in the second bed is saturated with methylacetylene and alleneand in Step (b) streams of inert gas are passed through the beds ofsaturated activated carbon thereby desorbing the acetylenic compoundsand forming a gas stream that contains 30 to 50 mole percent ofdiacetylene and vinylacetylene in said inert gas and a gas stream thatcontains 30 to 50 mole percent of methylacetylene and allene in saidinert gas.

3. The process for the separation of acetylenic compounds having threeor four carbon atoms from a hydrocarbon pyrolysis gas that contains from1 mole percent to mole percent of said acetylenic compounds thatcomprises-the following steps:

a. passing said hydrocarbon pyrolysis gas through a bed of activatedcarbon until the'surface of the carbon is saturated with adsorbedacetylenic compounds having three or four carbon atoms and passing astream of inert gas that is a mixture comprising 50 to 75 mole percentof nitrogen and 25 to 50 mole percent of methylene chloride through abed of saturated activated carbon thereby desorb ing the acetyleniccompounds and forming a gas stream that contains about 30 to 50 molepercent of acetylenic compounds having three or four carbon atoms innitrogen.

4. The process for the separation of acetylenic compounds having threeor four carbon atoms from a hydrocarbon pyrolysis gas that contains from1 mole .percent to 10 mole percent of said acetylenic compounds thatcomprises the following steps:

a. mixing the hydrocarbon pyrolysis gas with about 30 percent to 70percent of its weight of an inert, non-explosive gas that has carbonadsorption characteristics similar to those of diacetylene andvinylacetylene,

b. passing the resultinggasrnixt ure through a bed of activated carbonuntil the surface of the carbonis' saturated with adsorbed acetyleniccompounds having three or four carbon atoms and said inert,non-explosive gas, and

c. passing a stream of inert gas through the bed of saturated activatedcarbon thereby desorbing the acetylenic compounds and said inert,non-explosive gas and forming a gas stream that contains about 30 to 50mole percent of acetylenic compounds and said inert, non-explosive gasin said inert gas. 5. The method of claim 4 wherein the hydrocarbonpyrolysis gas is mixed with about 45 percent to 60 per-v cent of itsweight of said inert, non-explosive gas."

f 6. The method of claim 4 wherein the inert, non-ex-v plosive gas withwhich the pyrolysis gas is mixed is nbutane. r Y 7. The process for theseparation of acetylenic compounds having three or four carbon atomsfrom a hydrot :arbon. pyrolysis gas stream that contains from 1molepercent to 10 mole percent of said acetylenic compounds thatcomprises the steps of 4 a. passing the hydrocarbon pyrolysis-gas into afirst bed of activated carbon and the gas leaving said first bed into asecond bed of activated carbon until the surface of the carbon in thefirst bed is saturated with diacetylene and vinylacetylene and thesurface of the carbon in the second bed is saturated withmethylacetylene and allene and passing into each of said beds ofgas-saturated carbon a stream of inert gas that is a mixture comprising50 to 75 mole percent of nitrogen and 25 to 50 mole percent of methylenechloride thereby desorbing the acetylenic compounds and forming gasstreams that contain 20 to 50 mole percent of said acetylenic compoundsin nitrogen.

8. The process of claim 7 wherein "in Step (b) the stream of nitrogenand methylene chloride is 'passed through said first bed of saturatedactivated carbon to form a gas stream that contains about 20 to 50 molecomprises diacetylene and nitrogen is passed through a liquid nitrogentrap to condense the nitrogen and yield substantially pure diacetylene.

10. The process of claim 7 wherein the inert gas used to separate theacetylenic compounds from the gassaturated carbon is nitrogen saturatedwith methylene chloride at ambient temperature.

1 l. The process for the separation of acetylenic compounds having threeor four carbon atoms from a hydrocarbon pyrolysis gas that contains from1 mole percent to 10 mole percent of said acetylenic compounds thatcomprises the steps of a. mixing the hydrocarbon pyrolysis gas withabout 30 percent to percent of its weight of an inert, non-explosive gasthat has an afi'inity for carbon adsorption that is similar to that ofdiacetylene and vinylacetylene,

b. passing the resulting gas mixture into a first bed ofactivated'carbon and the gas leaving the first bed into a second bed ofactivated carbon until the surface of the carbon in said first bed issaturated with diacetylene, vinylacetylene, and said inert,non-explosive gas and the surface of the carbon in the second bed issaturated with methylacetylene, allene, and said inert, non-explosivegas and c. passing into each of said beds of gas-saturated carbon astream of inert gas that is a mixture comprising 50 to 75 mole percentof nitrogen and 25 to 50 mole percent of methylene chloride therebydesorbing the acetylenic compounds and the inert, non-explosive gas fromthe surface of the carbon and forming gas streams that contain to 50mole percent of said acetylenic compounds and said inert, non-explosivegas in nitrogen.

12. The process of claim 11 wherein the inert, nonexplosive gas isn-butane.

13. The process of claim 11 wherein the gas stream that contains 20 to50 mole percent of diacetylene, vinylacetylene, and said inert,non-explosive gas in nitrogen is passed through a sulfuric acid scrubberto v form a gas stream that contains diacetylene, the nonexplosive gas,and nitrogen.

14. A non-explosive composition that comprises activated carbon on whosesurface has been adsorbed 2 percent to 5 percent, based on the weight ofactivated carbon, of an acetylenic component selected from the groupconsisting of methylacetylene, diacetylene, vinylacetylene, and mixturesthereof and 2 percent to 5 percent, based on the weightof activatedcarbon, of an inert, non-explosive gas having carbon adsorptioncharacteristics similar to those of diacetylene and vinylacetylene.

15. The composition of claim 14 wherein the acetylenic componentcomprises diacetylene.

16. The composition of claim 14 wherein the acetylenic component is-amixture of diacetylene and vinylacetylene.

17. The composition of claim 14 wherein the inert, non-explosive gas isn-butane.

18. The composition of claim 14 wherein the-inert, non-explosive gas isethyl chloride.

2. The process of claim 1 wherein in Step (a) the hydrocarbon pyrolysisgas is passed into a first bed of activated carbon and the gas leavingsaid first bed is passed into a second bed of activated carbon until thesurface of the carbon in the first bed is saturated with diacetylene andvinylacetylene and the surface of the carbon in the second bed issaturated with methylacetylene and allene and in Step (b) streams ofinert gas are passed through the beds of saturated activated carbonthereby desorbing the acetylenic compounds and forming a gas stream thatcontains 30 to 50 mole percent of diacetylene and vinylacetylene in saidinert gas and a gas stream that contains 30 to 50 mole percent ofmethylacetylene and allene in said inert gas.
 3. The process for theseparation of acetylenic compounds having three or four carbon atomsfrom a hydrocarbon pyrolysis gas that contains from 1 mole percent to 10mole percent of said acetylenic compounds that comprises the followingsteps: a. passing said hydrocarbon pyrolysis gas through a bed ofactivated carbon until the surface of the carbon is saturated withadsorbed acetylenic compounds having three or four caRbon atoms and b.passing a stream of inert gas that is a mixture comprising 50 to 75 molepercent of nitrogen and 25 to 50 mole percent of methylene chloridethrough a bed of saturated activated carbon thereby desorbing theacetylenic compounds and forming a gas stream that contains about 30 to50 mole percent of acetylenic compounds having three or four carbonatoms in nitrogen.
 4. The process for the separation of acetyleniccompounds having three or four carbon atoms from a hydrocarbon pyrolysisgas that contains from 1 mole percent to 10 mole percent of saidacetylenic compounds that comprises the following steps: a. mixing thehydrocarbon pyrolysis gas with about 30 percent to 70 percent of itsweight of an inert, non-explosive gas that has carbon adsorptioncharacteristics similar to those of diacetylene and vinylacetylene, b.passing the resulting gas mixture through a bed of activated carbonuntil the surface of the carbon is saturated with adsorbed acetyleniccompounds having three or four carbon atoms and said inert,non-explosive gas, and c. passing a stream of inert gas through the bedof saturated activated carbon thereby desorbing the acetylenic compoundsand said inert, non-explosive gas and forming a gas stream that containsabout 30 to 50 mole percent of acetylenic compounds and said inert,non-explosive gas in said inert gas.
 5. The method of claim 4 whereinthe hydrocarbon pyrolysis gas is mixed with about 45 percent to 60percent of its weight of said inert, non-explosive gas.
 6. The method ofclaim 4 wherein the inert, non-explosive gas with which the pyrolysisgas is mixed is n-butane.
 7. The process for the separation ofacetylenic compounds having three or four carbon atoms from ahydrocarbon pyrolysis gas stream that contains from 1 mole percent to 10mole percent of said acetylenic compounds that comprises the steps of a.passing the hydrocarbon pyrolysis gas into a first bed of activatedcarbon and the gas leaving said first bed into a second bed of activatedcarbon until the surface of the carbon in the first bed is saturatedwith diacetylene and vinylacetylene and the surface of the carbon in thesecond bed is saturated with methylacetylene and allene and b. passinginto each of said beds of gas-saturated carbon a stream of inert gasthat is a mixture comprising 50 to 75 mole percent of nitrogen and 25 to50 mole percent of methylene chloride thereby desorbing the acetyleniccompounds and forming gas streams that contain 20 to 50 mole percent ofsaid acetylenic compounds in nitrogen.
 8. The process of claim 7 whereinin Step (b) the stream of nitrogen and methylene chloride is passedthrough said first bed of saturated activated carbon to form a gasstream that contains about 20 to 50 mole percent of diacetylene andvinylacetylene in nitrogen and said gas stream is passed through asulfuric acid scrubber to give a gas stream that comprises about 20 to40 mole percent of diacetylene and about 60 to 80 mole percent ofnitrogen.
 9. The process of claim 8 wherein the gas stream thatcomprises diacetylene and nitrogen is passed through a liquid nitrogentrap to condense the nitrogen and yield substantially pure diacetylene.10. The process of claim 7 wherein the inert gas used to separate theacetylenic compounds from the gas-saturated carbon is nitrogen saturatedwith methylene chloride at ambient temperature.
 11. The process for theseparation of acetylenic compounds having three or four carbon atomsfrom a hydrocarbon pyrolysis gas that contains from 1 mole percent to 10mole percent of said acetylenic compounds that comprises the steps of a.mixing the hydrocarbon pyrolysis gas with about 30 percent to 70 percentof its weight of an inert, non-explosive gas that has an affinity forcarbon adsOrption that is similar to that of diacetylene andvinylacetylene, b. passing the resulting gas mixture into a first bed ofactivated carbon and the gas leaving the first bed into a second bed ofactivated carbon until the surface of the carbon in said first bed issaturated with diacetylene, vinylacetylene, and said inert,non-explosive gas and the surface of the carbon in the second bed issaturated with methylacetylene, allene, and said inert, non-explosivegas and c. passing into each of said beds of gas-saturated carbon astream of inert gas that is a mixture comprising 50 to 75 mole percentof nitrogen and 25 to 50 mole percent of methylene chloride therebydesorbing the acetylenic compounds and the inert, non-explosive gas fromthe surface of the carbon and forming gas streams that contain 20 to 50mole percent of said acetylenic compounds and said inert, non-explosivegas in nitrogen.
 12. The process of claim 11 wherein the inert,non-explosive gas is n-butane.
 13. The process of claim 11 wherein thegas stream that contains 20 to 50 mole percent of diacetylene,vinylacetylene, and said inert, non-explosive gas in nitrogen is passedthrough a sulfuric acid scrubber to form a gas stream that containsdiacetylene, the non-explosive gas, and nitrogen.
 14. A non-explosivecomposition that comprises activated carbon on whose surface has beenadsorbed 2 percent to 5 percent, based on the weight of activatedcarbon, of an acetylenic component selected from the group consisting ofmethylacetylene, diacetylene, vinylacetylene, and mixtures thereof and 2percent to 5 percent, based on the weight of activated carbon, of aninert, non-explosive gas having carbon adsorption characteristicssimilar to those of diacetylene and vinylacetylene.
 15. The compositionof claim 14 wherein the acetylenic component comprises diacetylene. 16.The composition of claim 14 wherein the acetylenic component is amixture of diacetylene and vinylacetylene.
 17. The composition of claim14 wherein the inert, non-explosive gas is n-butane.
 18. The compositionof claim 14 wherein the inert, non-explosive gas is ethyl chloride.